Comparison of retention and stability of two implant-retained overdentures based on implant location.

Statement Of Problem: The location of dental implants and the choice of retentive attachments for implant-retained overdentures are selected based on clinician preference, expert opinion, or empirical information. Limited information is available regarding implant position and the effect on the retention and stability of 2-implant mandibular implant overdentures.

Purpose: The purpose of this investigation was to evaluate the effect of implant location on the in vitro retention and stability of a simulated 2-implant-supported overdenture and to examine the differences among different attachment systems.

Comparison of retention and stability of implant-retained overdentures based upon implant number and distribution.

Purpose: The purpose of this investigation was to evaluate the effects of number and distribution of implants upon in vitro dislodging forces to a simulated implant-supported overdenture and to examine differences between several different attachment systems.

Materials And Methods: An experiment was undertaken utilizing a model simulating a mandibular edentulous ridge with dental implants in positions on the model approximating tooth positions in the natural dentition. A cobalt-chromium-cast testing framework was used to measure the peak load required to disconnect an attachment.

An accelerated clinical chairside technique for casting overdenture attachment copings.

An accelerated technique for casting a direct-pattern post and core restoration for use in fixed prosthodontics has been previously described. Similar techniques for use in removable prosthodontics show potential for clinical use, specifically for the fabrication of radicular stud overdenture attachments and their corresponding copings. The procedure uses a chairside technique and readily available components to fabricate a direct, acrylic resin pattern combining the elements of a cast coping with a fixed radicular attachment.

Conversion of a partial removable dental prosthesis from Kennedy class II to class III using a dental implant and semiprecision attachments.

This article presents a design to convert a partial removable dental prosthesis (PRDP) from Kennedy class II to class III using a dental implant. Incorporating semiprecision attachments, this design provides desired esthetics, phonetics, and function.

Effect of axial height and palatal wall on the resistance form of a maxillary anterior metal-ceramic crown preparation.

The effect of palatal wall modifications and height of a maxillary central incisor on the resistance form of metal-ceramic crowns are compared. Dies with adequate preparation height show no crown dislodgement in groups with a palatal wall, palatal wall/groove, and no palatal wall. This study suggests the use of a palatal groove improves the resistance to dislodgement in short maxillary anterior tooth preparations.

Linguoaxial wall and cervicoincisal dimension of anterior crown preparation: effect on retention.

This study sought to evaluate the effect of the linguoaxial wall, a lingual auxiliary groove, and the cervicoincisal dimension of the anterior tooth preparation on retention. A simulated maxillary central incisor was prepared following "ideal" guidelines. The linguoaxial wall of these preparations was modified and the samples were divided into three groups: preparations with a linguoaxial wall (Group 1), preparations with a linguoaxial wall and groove (Group 2), and preparations with no linguoaxial wall (Group 3).

The effectiveness of auxiliary features on a tooth preparation with inadequate resistance form.

Statement Of Problem: No study has evaluated the efficacy of auxiliary tooth preparation elements for crowns with originally reduced resistance form.

Purpose: This study evaluated the effects of different auxiliary preparation features on the resistance form of crowns with reduced axial wall and total occlusal convergence.

Material And Methods: An Ivorine tooth was prepared on a milling machine with 20-degree total occlusal convergence (TOC), 2.

Peri-implant tissue response of immediately loaded, threaded, HA-coated implants: 1-year results.

Statement Of Problem: Although high success rates have been reported with immediately loaded implants, the peri-implant tissue response has not been well documented.

Purpose: This study evaluated implant success and peri-implant tissue response of immediately loaded, threaded, hydroxyapatite (HA)-coated root-form implants supporting mandibular bar overdentures with opposing conventional maxillary complete dentures in humans.

Material And Methods: Five patients (3 men, 2 women; mean age 61 years) each received 4 HA-coated endosseous root-form implants in the interforaminal region in the mandible.

Tooth preparations for complete crowns: an art form based on scientific principles.

Statement Of The Problem: No recent literature has reviewed the current scientific knowledge on complete coverage tooth preparations.

Purpose: This article traces the historic evolution of complete coverage tooth preparations and identifies guidelines for scientific tooth preparations.

Material And Methods: Literature covering 250 years of clinical practice was reviewed with emphasis on scientific data acquired during the last 50 years.

The swing-lock removable partial denture.

The swing-lock removable partial denture is a good treatment alternative for maxillofacial prosthodontics, periodontally compromised dentitions and where some conventional designs for removable partial dentures cannot be applied. This paper presents clinical applications of the SLRPD. Indications, contraindications, advantages and disadvantages are discussed.

The component partial: a new RPD construction system.

Most removable partial denture frameworks constructed today are one-piece castings. This article presents the Component Partial, a removable partial denture in which the framework is constructed in pieces. Such construction ensures a more accurate fit of the RPD.

A comparison of an accelerated technique for casting post-and-core restorations with conventional techniques.

Purpose: This project compares an accelerated technique for the casting of post-and-core restorations with four traditional techniques. The accelerated technique uses two phosphate-bonded investments and the traditional techniques use a gypsum- and a phosphate-bonded investment. The study measures and compares the differences between the seating of the casting and the seating of the acrylic resin pattern.

An accelerated technique for casting post and core restorations.

An accelerated technique for casting a direct-pattern post and core restoration is presented. The entire clinical and laboratory procedure may be completed within 1 hour. The necessity for two appointments for completion of the restoration as well as the necessity of making two provisional restorations may be eliminated.

Color consistency, plaque accumulation, and external marginal surface characteristics of the collarless metal-ceramic restoration.

Four techniques for making collarless metal-ceramic restorations were investigated in this study to examine the final color consistency, the bacterial plaque accumulation, and the surface characteristics of the porcelain margin. Twenty crowns were constructed and data revealed the superiority of the platinum foil technique in producing consistent color, whereas the shoulder porcelain technique resulted in the most significant color deviation. Metal surfaces exhibited the greatest in vitro bacterial plaque accumulation (42.

A comparison of the stress transfer characteristics of a dental implant with a rigid or a resilient internal element.

It has been suggested that there is a unique set of problems associated with joining an implant and a natural tooth with a fixed partial denture. The manufacturer of the IMZ implant system claims that this procedure can be accomplished successfully because of the planned stress-distributing characteristics of their resin internal (intramobile) element. This study compared the difference in the stress patterns generated in photoelastic plastic by an IMZ implant with a resilient or a rigid internal element.

The effects of a liquid dispersing agent and a microcrystalline additive on the physical properties of type IV gypsum.

This study evaluated the effects of a liquid dispersing agent (LDA) and a microcrystalline additive (MCA) on selected physical properties of type IV gypsum. Working consistency, setting time, setting expansion, and compressive strength (1 hour and 7 days) were determined, following ADA Specification No. 25, on a standard, LDA (0.

Effect of die spacer on the seating of complete cast gold crowns with grooves.

Fifty crowns were constructed with an indirect technique for a standardized Ivorine tooth preparation to determine whether casting relief would improve the seating of complete cast crowns with zinc phosphate cement. The variables were two grooves in the preparations and die spacer casting relief of approximately 20 to 40 micron. The tooth preparations of two groups had no grooves, but castings were made with internal relief for only one group.

Simplified techniques for the preparation and use of reversible hydrocolloid impression material.

The use of a simple technique with an inexpensive syringe loaded with heavy-body tray material resulted in a savings of preparation time and storage space in the conditioning unit. Only one type of material needs to be liquefied. The use of the heavy-body material in syringe and tray in conjunction with a hydrophilic technique have practically eliminated the annoying problem of tearing of the material in the gingival crevice on removal of the impression.

Technique for cementation of provisional restorations.

A technique for cementation of a provisional resin splint or crown has been presented. The splint is lubricated with silicone grease and cemented with a noneugenol cement mixed with antibiotic ointment. The grease aids in the complete removal of the cement.

Use of paint-on die spacers in preparations with grooves.

Film thickness of paint-on die spacer materials was measured on axial walls and in grooves. Two different materials and two different modes of application were tested. From the data presented, the following conclusions can be drawn: There are potentially significant differences in film thickness produced with different die spacing materials.